Spark plug



Dec. 26, 1933. F A, SHARPNACK 1,941,279

` SPARK lLUG l original Filed May 29', 1930 ,j e y one-half to Byron A. `Hathaway and William v y f atented Dec. l I, Y i t y 1,941,2'19`IA `A SPARK PLUG Frank A. Sharpnack, Chicago, Ill., assignor of B. Fox, both of Chicago, Ill. '1

vApplication May 29, 1930),` SerialNo. 457,120 Renewed August 15, 1933 VV2 Claims. (01123-169) y This invention relates to sparkplugs, and .its construction set out in Fig. 2 one or more rings l object is the production of a new article of manuof 'asbestos packing 8 may be introduced. facture consisting in a sparkplug having its core In Fig. 3 which illustrates the preferred form composed of a refractory, insulating and' pracof this invention, the body'9 is entirely of Lavite M 5'tical1y unbreakable materialv known to the trade and the screwthreads. 10 are cut directly there- 60" as Lavite, or the entire body of the'plug may be in. A U-shaped electrode 11 is secured in the of Lavite only, there being no metal therein exk.lower end `of the body in such a manner `that it V cepting the electrodes. will make metallic contact with the threadsvin It is ,also an object of this inventionto ,p roa cylinder head when itis placed thereon.y It i-vide a sparkplugof the nature stated and having vwill be noted in Fig. 3 that the axial electrode is 65 parts of special construction and arrangement surrounded by a plurality of spaced recesses 12 as set forth in the accompanying drawing of and 13 formed in the lower end ofthe body 9. which Fig. 1 represents a side view of aspark- Laviteis a compound of substantially the followy plug of the customary construction providedwith ing ingredientsz-silica 47.40%; magnesium oxu 15 'ia Lavite core. Fig. 2 shows a sparkplug partly ide 48.23%; lime .'.64%; free iron and aluminum 70 i in vertical section and having a removable sleeve 3.97%.y `It is not only specially resistant to heat of insulating materials surrounding the* axial and relatively unbreakable, but it is alone the electrode and arranged to create a plurality of satisfactory insulating substance found by this spaced recesses. about that electrode. Fig. 3 applicant after extended and expensive trials` Ashows a sparkplug with a body composed solely .that will permit the formation of screw threads 75 'i of refractory insulation,-i.- e. Lavite and having ,directly in its surface, and whichis sufficiently its lower part formed with spaced recesses. Fig. Ytough to keep those threads intact, practically 4 shows a sparkplug as in Fig. 3 with the body",v the same as if the threads were cut in metaLwhen composed solely of Lavite with the exception of the plug is setup in the cylinder head by a lthe electrodes and a: metal sleeve bearing the wrench, and which exhibits no damageby rea- 90.5?"

external threads. Fig. 5 illustrates a sparkplug son of the often rough handling sparkplugs i comtructed in accordance with this 'invention receive.r ,l and placed in a cylinderhead, shown in section, Fig. 4sets out the same construction as Fig. 3, and providing a plurality of spark rgaps in the withthe exception that there maybe used on 36"ignition circuit. Figs. 6 and 7 are lower end body 14 a metal sleeve 15 which bears the ex- 55 views of Figs. 3 and 4. A ternalgnecessary threads. .The tlf-shaped elec- Throughout the description and drawing, the trodeY 16, or whatever form of velectrode is used same number is 4used vto refer to the same part.V may be secured in the sleeve 15. l Considering Fig.l1, the plug is of the usual Fig. 5 shows the .all Lavite body 17 of the 35' construction designated 1, and it is provided with"y sparkplug screwed into a cylinder headY 18. It 90 I" a core of refractory material 2 known to the Will be noted that the U-shapedelectrode 19 "trade as `Lavite. In, this invention it is held .to terminates in the body opposite the openings20.

be the right of the applicant to use any other In the operation, additional sparks are provided at" insulating and practicallyV unbreakable material such openings giving to this invention the fonn ,l

1o-which has the same properties and tothe same and advantage lof those sparkplug inventions 95' extent as Lavite. That is to say, the material which havetherein a plurality ofspark gaps. is verydiflicultk to break, 'it will not chip or b urnv .,Fig's; 6 and 7 show bottom views of the p arts or melt away when usedjas the body of a sparkas illustrated in Figs. 3 and 4 and show the spacedv plug. j y As shown in Fig. 2 vthe plug 3 has aI core`4 ofVV concentrically. The plural recesses are found by 100 the material specified, Vand a removable ,sleevev experience and extended trials to prevent or in v 5, which is of insulating material advantageously` some Way to keep the electrodes ofthe sparkplug Y of Lavite. The arrangement of the core and ,wholly free from carbon deposits. f sleeve and external portions of the sparkplug The operation of this invention isthe same as 50 Aas set out in Fig. 2-results in a plurality of spaced that of any sparkplug, its believed" superiority or 105 recesses 6 and 7 around the axialelectrode of improvement over those with which applicant is the plug `and `spaced from each other. This arfamiliar residing in thewhole Lavit'efbody and rangement is found by experience to maintain the recessed lower portionas described. Y 1 the plug in continuous and extended use without Having now described this invention and ex- 56' any accumulation of carbon thereon.` In the plained its use,I claimz-` J ,f recesses Vusuallycylindrical inform and disposed .fr

2. As a new article of manufacture, a sparkplug having a body formed of refractory insulating material, said sparkplug having electrodes carried by said body, said body having its end portion provided with external screw threads constructed and arranged to be screwed into a motor cylinder head, one of said electrodes being arranged in proximity to said external threads and exposed to the exterior, and the lower end of said body being formed into a plurality of spaced skirts.

FRANK A. SHARPNACK. 

